"Well, I speak the most Italian, so I'll be your escort. Donowitz speaks the second most, so he'll be your Italian cameraman. Omar speaks third most, so he'll be Donny's assistant."

"I don't speak Italian."

"Like I said, third best."

“oh, I know that language too!” from someone. And… They don’t.

Prime example: according to numerous surveys more Dutch people speak French well than Belgians.

Belgian is half French speaking, French is taught in Flemish schools from an early age, and many Dutch/Flemish speakers work in predominantly French speaking Brussels, and/or have French speaking friends/relatives.

But it's understandable: a Dutch person thinks their French is great if they manage to order something in a French restaurant while on holiday and have the waiter understand them. That's more than enough for their purposes. A Flemish Belgian thinks their French is bad, if they're unable to write a letter in French which respects rules like those about accord COD/COI (Elle a pris des photos. Les photos qu'elle a prises. Elle est allée prendre des photos. - Hope that's correct)

That and Dunning Kruger. If you have little competence in foreign languages, you don't know enough to know that you don't know enough.

This is broadly true with white Americans that their immigrant background is there already for generations... but a huge part of america does not even speak English at home. America is a melting pot of people from everywhere in the world.